FIGS. 3(A)-3(C) are views showing a conventional connecting electrode used in a semiconductor device card, in which FIG. 3(A) is a plan view and FIGS. 3(B) and 3(C) are sectional views taken along lines III(B)--III(B) and III(C)--III(C) of FIG. 3(A), respectively. In FIGS. 3(A)-3(C) reference numeral (1) designates a planar electrode substrate and reference numeral (2) designates a contact provided on the electrode substrate (1) and formed of a spring material, which has a convex surface (3) bent like a buttonhook and projecting from the electode substrate (1). The electrode substrate (1) and the contact (2) comprise the connecting electrode.
FIGS. 4(A)-4(C) are views in which the connecting electrode shown in FIG. 3 is mounted on a semiconductor device card with a battery in place. FIG. 4(A) is a plan view thereof and FIGS. 4(B) and 4(C) are sectional views taken along lines IV(B)--IV(B) and IV(C) --IV(C) in FIG. 4(A), respectively. Reference numeral (4) designates a frame of the semiconductor device card on which the electrode substrate (1) is mounted. Reference numeral (5) designates a battery pressed toward the right in FIG. 4(C), that is, toward the convex surface (3) of the contact (2) by means not shown.
Next, operation thereof will be described hereinafter. When one electrode of the battery (5) (not shown) is pressed against the contact (2) bent like a buttonhook as shown in FIGS. 3(B) and 3(C), the contact (2) receiving the force extends its bending part (6) and finally deforms into a straight line, that is, it is completely compressed as shown in FIGS. 4(B) and 4(C). Electrical connection between the battery (5) and the contact (2) is maintained by the elastic force by which the contact (2) tries to return to the original shape of a buttonhook. The other electrode of the battery (5) (not shown) is appropriately connected and then electric power is supplied to an electric circuit (not shown) of the semiconductor device card.
Since the conventional connecting electrode is constructed as described above, the force generated when the battery is in place completely compresses the contact. At this time, excessive stress is generated thereon and contact pressure between the battery and the contact generated by the elasticity of the contact is reduced due to fatigue or creep caused by vibration. As a result, the battery is not in contact with the contact when it receives external vibrations and then power supply is not applied to the electric circuit, causing stored information to be erased.